Add percentages instead of counts to countplot

[hnykda]

Hello,

I would like to make a proposal - could we add an option to a countplot which would allow to instead displaying counts display percentages/frequencies? Thanks

[mwaskom]

As of v0.13, normalization is built directly into countplot:

sns.countplot(diamonds, x="cut", stat="percent")  # or "proportion"

The recommendation is otherwise to use histplot, which has a flexible interface for normalizing the counts (see the stat parameter, along with common_norm), although its defaults are not identical to countplot so you'll need to be mindful of that. Here's an example:

sns.histplot(tips, x="day", hue="sex", stat="percent", multiple="dodge", shrink=.8)

---

Original answer (context for the rest of the thread):

This is already pretty easy to do with barplot, e.g.

import numpy as np
import pandas as pd
import seaborn as sns

df = pd.DataFrame(dict(x=np.random.poisson(4, 500)))
ax = sns.barplot(x="x", y="x", data=df, estimator=lambda x: len(x) / len(df) * 100)
ax.set(ylabel="Percent")

[hnykda]

Oh! y="x" was that missing piece! :D

IMHO it would worth to add this example somewhere in the docs.

Thanks

[napsternxg]

Unfortunately, this doesn't work if both x and y are non_numeric. I get the following error:

sns.__version__
'0.7.0'

ax = sns.barplot(x="name", y="name",
                 estimator=lambda x: len(x),
                 data=df, color="grey")

/PATHTO/anaconda2/lib/python2.7/site-packages/seaborn/categorical.pyc in infer_orient(self, x, y, orient)
    343         elif is_not_numeric(y):
    344             if is_not_numeric(x):
--> 345                 raise ValueError(no_numeric)
    346             else:
    347                 return "h"

ValueError: Neither the `x` nor `y` variable appears to be numeric.

[mwaskom]

Pass orient="v" to avoid the attempt to avoid inferring the orientation, or pass any numerical column to y (it doesn't have to be the same as the x variable).

[hnykda]

Sorry for opening this again, but it seems that the provided solutions doesn't work with hue parameter. Is there some other tweak fixing this?

[mwaskom]

Can you be specific about what "didn't work"? If you look at the code, you'll see that all countplot is doing is making a barplot with a len estimator and the same variable used for x and y, so it's not obvious to me what your problem might be.

[hnykda]

I should have been more specific, sorry for my stupidity... I currently can't replicate the problem, so never mind.

[beniz]

The example above does not work for me, somehow it plots a flat distribution whereas df is correctly populated with the Poisson samples. Using 0.7.1 from pip.

[gandhis1]

I do agree this would be a great example for docs.

[beniz]

To be very honest, more than that, having a percentage option right within countplot would clear this issue once and for all, and given the number of entries on stackoverflow, it'd be great :)

As an OSS project maintainer myself, I definitely know how annoying these requests can be. @mwaskom if I were able to fix this myself in decent time, I would PR, but I can't event get it to work ^^.

[mwaskom]

It is not so obvious because different people will want different behaviors in the context of hue nesting and faceting. However it should always be possible for people to make the plot they want by defining the heights and using barplot. I would be happy to advise but as stated above, it is impossible to know what your problem is from saying "it does not work for me".

[rselover]

I'm having trouble reproducing @mwaskom's original response with my own dataset.

A big part is I don't understand the logic of y="x" and am also confused by the use of x in the lambda function vs x="x". Can you elaborate?

Furthermore, I'm having trouble porting this to a Facetgrid (which works great with countplot, just don't have proportions).

Here's an example of what works -

g = sns.FacetGrid(df, col="Cluster_3_0")
g.map(sns.countplot,x=df['zone_number'],
#y=df['zone_number'],
#estimator=(lambda x: len(x) / len(df) * 100),
order=([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]))

When I uncomment y & estimator, (or even just y), the kernel crashes after several non-responsive minutes.